5. Robotic Puppets and the Engineering of Autonomous Theater

This chapter outlines the design of software for embedded control of robotic marionettes using choreography. In traditional marionette puppetry, the puppets often possess dynamics that are quite different from the creatures they imitate. Puppeteers must therefore understand and leverage the inherent dynamics of the puppets to create believable and expressive characters. Because marionettes are actuated by strings, the mechanical description of the marionettes either creates a multiscale or degenerate system—making simulation of the constrained dynamics challenging. Moreover, marionettes have 40–50 degrees of freedom with closed kinematic chains. Generating puppet choreography that is mimetic (that is, recognizably human) results in a high-dimensional nonlinear optimal control problem that must be solved for each motion. In performance, these motion primitives must be combined in a way that preserves stability, resulting in an optimal timing control problem. Our software accounts for the efficient computation of the (1) discrete time dynamics that preserve the constraints and other integrals of motion, (2) nonlinear optimal control policies (including optimal control of LTV systems), and (3) optimal timing of choreography, all within a single framework. We discuss our current results and the potential application of our findings across disciplines, including the development of entertainment robots and autonomous theater.